Home/CVE/In the Linux kernel, the following vulnerability has been resolved:
netfilter: xt_CT: drop pending enqueued packets on
CVE
CVE-2026-23391
In the Linux kernel, the following vulnerability has been resolved:
netfilter: xt_CT: drop pending enqueued packets on
In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_CT: drop pending enqueued packets on template removal Templates refer to objects that can go away while packets are sitting in nfqueue refer to: - helper, this can be an issue on module removal. - timeout policy, nfnetlink_cttimeout might remove it. The use of templates with zone and event cache filter are safe, since this just copies values. Flush these enqueued packets in case the template rule gets removed.
HIGH · CVSS 7.8
EPSS 0.00022
EPSS exploitation odds0.02% · top 93%
Schedule remediation
- CVSS base score ≥ 7.0
No Sigma yet — build one →
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-23391, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
CVSS base score
7.8
HIGHCVSS v3.1 · 416baaa9-dc9f-4396-8d5f-8c081fb06d67
EPSS exploitation probability
0.02%
Top 93%odds of exploitation in the next 30 days
CVSS metric silhouette
shape grows toward worst-case
CVSS vector breakdown
Exploitability - how they get in
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Impact - what breaks
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
VECTOR
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLifecycle
- 25 Mar 2026Published to NVD
- 24 Apr 2026Last modified
Every entry is a recorded date - NVD publish/modify, CISA KEV add, public exploit disclosure. No inferred events.
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ATT&CK techniques
1Techniques this CVE enables - linked via CWE → CAPEC → ATT&CK. Pills with a solid outline are named directly in ATT&CK or Nuclei templates (high confidence); the others are linked through weakness mappings.
▤ Build a SIEM detection for these techniques▤
Affected Products & Versions
8linux kernel>= 3.4.1 and < 5.10.253
linux kernel>= 5.11 and < 5.15.203
linux kernel>= 5.16 and < 6.1.167
linux kernel>= 6.2 and < 6.6.130
linux kernel>= 6.7 and < 6.12.78
linux kernel>= 6.13 and < 6.18.20
linux kernel>= 6.19 and < 6.19.10
linux kernelall versions
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Related CVEs
6CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.
CVE-1999-1442
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CVE-1999-1285
Linux 2.1.132 and earlier allows local users to cause a denial of service (resou...
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CVE-1999-0656
The ugidd RPC interface, by design, allows remote attackers to enumerate valid u...
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CVE-1999-0431
Linux 2.2.3 and earlier allow a remote attacker to perform an IP fragmentation a...
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CVE-1999-1018
IPChains in Linux kernels 2.2.10 and earlier does not reassemble IP fragments be...
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CVE-1999-1341
Linux kernel before 2.3.18 or 2.2.13pre15, with SLIP and PPP options, allows loc...
same product
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Vendor Advisories
1msrcCVE-2026-23391
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References & Sources
8Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.